Centerboard pivot setup or modification.

[GreenLake]

I guess I'm more dense than usual, but I can't visualize your solutions. Any way to create a sketch or drawing to show what you did?

[K.C. Walker]

okay, I made a stab at a sketch.

KC

http://www.walkerguitars.com/boat/cente ... rboard.jpg

[GreenLake]

OK. Now I see

(Don't ask me where I thought you had placed those strips... )

Makes sense. you use maximal leverage for minimal added area that can cause friction.

Two questions remain. Polyethylene is hard to glue. How did you attach the strips? Screws?

The other question: What do you predict will happen when you get sand into the CB trunk?

My second boat is all polyethylene, and there's plenty of sand to go around where I launch it, so call me "experienced". In my case, it's chewed up the daggerboard somewhat ugly, as well as presumably the inside of the well. Added some friction as well, although I can't recall an instance of it being seriously stuck. Since it's a daggerboard you can really yank at it to try to free it, I think there's more force than you can apply easily to a DS CB.

Anyway, that's something I'd watch out for. If you don't launch from the beach, you should be fine.

[K.C. Walker]

OK.
Two questions remain. Polyethylene is hard to glue. How did you attach the strips? Screws?

The other question: What do you predict will happen when you get sand into the CB trunk?

My second boat is all polyethylene, and there's plenty of sand to go around where I launch it, so call me "experienced". In my case, it's chewed up the daggerboard somewhat ugly, as well as presumably the inside of the well. Added some friction as well, although I can't recall an instance of it being seriously stuck. Since it's a daggerboard you can really yank at it to try to free it, I think there's more force than you can apply easily to a DS CB.

Anyway, that's something I'd watch out for. If you don't launch from the beach, you should be fine.

Green Lake,

Yeah, screws, flat head and countersunk. The shims are about 1/8 inch thick.

So far, I have no experience with getting sand in it. My thoughts on using the strips were that it would be somewhat self clearing if it did get sand in it. When the board is up it only presents a small area for sand and then when the board rotates the shims slide to totally different positions. Also, the high density polyethylene is much harder than the standard stuff. It's extremely difficult to sand it. I don't think that's sand would be able to easily embed itself in the material.

I wasn't able to get out sailing this year as much as I would have liked due to "boat projects", but of the 15 or so trips it did take it's worked smooth as silk. It worked well enough that I'm actually thinking about how I might incorporate this into a new thicker board. I.e., would I make the head of the board thin enough to allow shims for final fitting to the centerboard trunk? I think I would.

I might make the strips narrower, though. After all, in reality, the top edge of the top shim and the bottom edge of the bottom shim are the bearing surfaces.

KC

[swiftsail]

I've been using good old contact cement for gluing in my centerboard shims for years. I works great.

[K.C. Walker]

I've been using good old contact cement for gluing in my centerboard shims for years. I works great.

Do I recall correctly that you are using Formica shims?

KC

[swiftsail]

Nope, I like to use good old Polypro signs. Then layer them to get the right thickness with contact cement. No screws to worry about. Depending on the boat, I've put shims on the top of the board and on the bottom edge of the centerboard opening.

[K.C. Walker]

Swiftsail, that sounds pretty straightforward and easy to build up the right shim dimension.

KC

[swiftsail]

One thing to remember is, if you want to be exact, you don't necessarily shim both sides equally. I put the boat on it's side with the mast up. Level the mast (assuming the is straight, side to side) I then level the board with the shims. That way at least the mast and the centerboard are in the same plane.

[K.C. Walker]

That way at least the mast and the centerboard are in the same plane.

Good point!